This invention concerns systems for cleaning storage tanks such as are in common usage in petrochemical plants or in oil refineries. More particularly, the invention concerns robotic systems for cleaning such tanks wherein shorter times for cleaning, safer working conditions for workers in the cleaning process, and tighter environmental controls on gaseous or noxious emissions can be achieved than were heretofore obtainable.
Storage tanks having diameters of from 20 to 150 feet are in common usage in refineries and chemical plants. Such tanks are generally closed to the atmosphere by floating or fixed roofs and thereby can contain noxious or aromatic liquids. With passage of time it may be desirable to convert such a tank to a different storage liquid or the tank may become fouled by sediment resulting from a chemical process or by rust, corrosion, or the like, and it becomes necessary to clean the interior of such tanks. Also certain tanks containing pyrophoric materials can be cleaned by this method without removing the purge or by continuously wetting the total internal area of the tank.